Method of and means for forming pipe bends



July 25, 1950 c, c oss 2,516,372

METHOD OF AND MEANS FOR FORMING PIPE BENDS Filed Sept. 1'7, 1945 5 Sheets-Sheet 1 CLINT CROSS INVENTOR.

u y 1950 c. cRoss METHOD OF AND MEANS FOR FORMING PIPE BENDS Filed Sept. 17, 1945 5 Sheets-Sheet '2 CLINT CROSS INVENTOR- ZM/fl%o w" y 5, 1950 CROSS- 2,516,372

METHOD OF AND MEANS FOR FORMING PIPE'BENDS Filed Sept. 1'7, 1945 5 Sheets-Sheet 3 gwuem kw CL INT CROSS July 25, 1950 F c. cRoss METHOD OF AND MEANS FOR FORMING PIPE BENDS Filed Sept. 17,- 1945 5 Sheets-Sheet 4 S m R C T W c July 25, 1950 c CROSS METHOD OF AND MEANS FOR FORMING PIPE BENDS 5 Sheets-Shet 5 Filed Sept. 17, 1 945 \AQM. mm 9. v ow W. 1 h on i CLINT CROSS INVENTOR.

Patented July 25, 1950 METHOD OF'AND MEANS FOR FORMING.

PIPE BENDS Clint Cross, Tulsa,0kla., as'signorto W. cnorris, Manufacturer, Inc., Tulsa, Okla.

Application September 17, 1945', Scrial'No. 61.6;835.

13 Claims. 1,

This invention relates to new and useful improvements in method of and means for forming pipe bends.

one object of the invention is to provide a method of forming pip bonds which involves certain improvements upon the methodssetiorth my co-pending application Serial No. 509,446;

filed November 8, 1943 (Patent No. 254566377;

granted April 12; 1949); I Another object of the invention is to provide anapparatus for forming pipe bends which involves certain improvements upon the apparatus set forth in the aforesaid co-pending application; A particular object of the invention is to provide an improved method of forming pipe bends witha short radius and tangential ends.

A further object of the invention is to provide an improved method of forming a pipe bond which includes supporting the pipe section and bending the ends uniformly while supporting the entire outer bend on a continuous single die and thereafter rounding out the bend.

Still another object of the invention is torprbvide an improved pipe bending apparatu's incl-uding a plunger having means for mounting a horn die thereon whereby said'die may be angularly adjusted with relation to the longitudinal: axis of" the plunger, as Well aswhereby, said die becomes self adjusting as the pipe bending opera tion progresses;

A. construction designed to carry out thein'vention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from areading of the following specification: and by reference to the accompanying drawings,v wherein an example of the; invention is shown, and wherein: i Fig. 1 is. aview of'an apparatus partly in elevation andipartly in section, constructed in accord ance with the invention and with all. dies re.- tracted',

Fig. 2v is a similar view showing: the; pipe sectionin place; for the. initial bending operation,-

: Fig. 3 is a view partly'in elevation and-partly insection, showing the bend completed,

Fig. 4 is a similar view showing the finishing:

die in .the pipev bend,

, Fig. 5 is a view of the horn die carrier, partly inelevation and partly in section,

Fig. dis a viewof one-of the'hydraulic cylinders and its support, partly in elevation and partly insection, and

Fig. 7 is a detail of the plug.

I the drawings; the numeral l0" designates a flat tableor support which may be mounted in any suitable way; On the support a stationafiy bending or forming die H is suitablymounted and coabts with a movable bending or forming die I 2 The die I 2 provided-with a shanlc I3 whereby it'may be attached to any suitable means formovingit toward and from the die H The dies are formed with complementary upright faces t4 each of which faces is provided with a transverseniedial sink or recess I5; It is pointed out that the central portions of the upright faces; I 4 are curved on a short radius as indicated at A, while the upright faces B extending from each end of theradiusare-struck at a tangent thereto. When the dies are brought together,- their faces will l'i'e inintimatecontact coincident to thecen-= ter line or longitudinal: of a pipe bend supportedin: thesinks l'5-L- While the sinks are substantially' semicircular in cross-section; they are also provided with curved faces C concentric to. the of the face portions A; while-the longitudinal end" portions D of the sinks: extend at tangents to the curvatures C and are parallel to the faces B. The sink of the die H is generally convex; while the sink of the die l2 is generally concaved.

The foregoing: construction of the: dies is very important, and contributes largely to th success of theinvention; In mak'in-g a pipe band, it is de sirable' to confinethe cur-vatureof the bend to a comparatively short section of the medial portier-r thereof and to confine such bend to'ashort radius; whereby'the ends of the-bend may extend at' tangents, and may either be short or long,

1 thuspermitting the formingof a variety of bends of various overall lengths,- as wel1= as preventing: bending of the-pipe metal on a wide radius. By observing- Figs 2' and 4 it will be noted that the stationary die I i has acentral face or ful crum G and thepipe section.- P constantly rests thereon; thus forming the inner medial portiono'r the bend; whereas, that portion of the-pipe bend formed in the faceflof the die I1 2, consti tutesi the outer medial, portion. of the pipe bend; When: the dies: H and L2 are: brought together;. as shown in Figs; 3 andA, itwill be observed that the ends of the faces [4. and the. endszof the sinks l5,.respectively,.will lie flush.

Oneach sideof the, stationary die [2, hydraulic; cylinders Iii and H are. mounted on the table Ill, in any suitable manner, and preferably unfrotatableplatforms lll'c'arriedby'the table It; The cylinder I6 is provided with a plunger rodj I9; while the. cylinder IT has a. plunger'rod' Zll'. It is not deemedne'cessaryto enter into a" detailed discussion of the hydraulic mechanism, because any suitable structure may be used, and furthermore, it would be possible to use mechanical means for operating th plungers. The longitudinal axis of each plunger is alined with the faces B when the dies are brought together, so as to be in longitudinal alinement with the completed ends of the pipe bend. a 1

On the end of the plunger 19,3, flanged head 2| is tightly fitted and held in place by a countervided with an annular seat 23, which receives an annular rim 24 of a die carrier 25. The die carrier is provided at one end with a shank 26, on which the rim is formed, and a split retaining ring 21 is clamped about the shank and rim. Machine bolts 29 screwed through the. ring 21 and the flange of the head 2| frictionally clamp the carrier 25 to the head, so that it is held against movement therein.

.The carrier 25 is curved so that its face adjacent to the dies H and I2 is concaved. The carrier includes upper and lower spaced plates 30, secured together by bolts 3|. At the inner end of the carrier, which is the end from which the shank, 26 extends, a space block 32 is disposed between the plates, while at the outer or opposite end, the plates are spaced apart by a block 33 provided with an outwardly flared recess 34.

A die chuck 35 is provided with an arcuate guide face 38 struck on a radius contiguou to the concaved face of the carrier 25, whereby said face may slide on the edges of the plates 30. The chuck is provided with a reduced and flattened ear 31, which has a snug sliding fit between the plates 30 and carries a vertical pin 38 extending through the ear and engaging in guide slots 39 in the plates concentric to the guide face 35. A headed rod 40 extending through the recess 34 is attached to the ear31, and may be used to slide the chuck in the carrier. Each slot 39 has at its inner end a sump 41 for receiving the pin 38. By giving the pin a snug sliding fit in the slots, it will tend to remain in the sump 4| when pushed thereinto. j I

The chuck 35 is provided with a socket'42 for receiving the reduced shank 43 of a horn die E. As best shown in Fig. 2, the shank is formed with an inclined seat 44 for receiving the end of a set-screw 45, which is screwed through the chuck so as to fasten the die in place. At its outer end, the horn die, which is generally cylindrical, is formed with a curved face 46, which is curved both longitudinally and transversely to substantially the same contour on which th inner face of the outer wall of the pipe is to be bent; thus the longitudinal curvature of the face 46 is con centric to the curvatures of the sections A and C of the movable die l2, so that when the dies II and I2 are brought together, as shown in Figs. 3 and 4, the curved face 46 will lie in intimate contact with the outer wall of the pipe P. It is further pointed out that the length of such face 46 determines the length of the bend of the pipe, and the pipe is initially bent to the radius of this face on each side of thetranssunk screw 22. The outer face of the head is pro- 4 whereby the bend is completed with the pipe ends at substantially right angles to the tangents.

In my co-pending application, supra, the pipe section was first placed in on end of the sink of the stationary die, and the opposite end of the pipe then bent, but in the present invention, it is proposed to bend both ends of the pipe section at the same time, and in order to do this, it is necessary to provide a plug 41 to be inserted in one end of the pipe when the horn die E is inserted in the other end to hold the pipe in round. The plug 41 is cylindrical so as to snugly fit in the end of the pipe, and is provided with an enlarged head 48, having a collar 49 rotatably mounted therein. The collar 48 is provided with a pair of diametrically oppositely directed trunnions 50 on which the forward ends of a pair of links 5| are pivoted. A yoke 52 is pivoted on the trunnions 53 between the rear ends of said links and is provided with a handle 54 whereby it maybe manipulated. A second or complementary horn die F i provided on the opposite side of the die I I from the die E and is provided with a reduced shank 55. This die is movable toward the dies II and i2 and when brought into proper position the yoke 52 ma be engaged over the shank 55 as a support. When the yoke is engaged on the shank 55 and the die F is re-, tracted, it will exert a pull whereby the plug 41 may be extracted from the pipe P. By reason of the links and pivoted collar, a swivel connection is made with the plug which permits the yoke to be adjusted to various positions.

The shank 55 is fitted snugly in a socket 56 in a chuck 5! which is mounted in a head 58 secured on the plunger 20 in a, manner similar. to the fastening of the head 21. The chuck 57 has an annular rim 59 engaging in a seat 60 in the head 58 and is secured by a split retaining ring 6| fastened to the head by bolts 62. The shank 55 has an inclined seat 63 receiving a set screw 64 screwed into the chuck for fastening the shank therein.

The first step of the method is the cutting of the pipe P to the desired length and with its ends at the proper angles. The pipe is then heated in a suitable furnace in any suitable manner under a forging temperature which is largely deter.- minedby the type of metal or allo from which said pipe is formed. Ordinarily, the forging temperature is somewhere between 1,200 and 2,400" F.; however, in. forging pipes of non-ferrous metal, the temperature may be much lower and may be even as low as 500 F.

The forming dies H and 12 having been separated as shown in Figs. 1 and 2, the horn die E is moved in the carrier 25 to the outer end thereof as shown in Fig, 2. The hydraulic cylinder lfiyhaving been previously positioned, is operated to extend the piston l9 so as to bring the horn die into the position shown in Fig. 2, The pipe P is then slipped over the die E and centered with respect to the ends of the sinks i5. It will be observed that the curved face 46 is'divided equally on opposite sides of the transverse center line XX (Fig. 3). The plug 4'! is'then inserted in the opposite end'of the pipe P, with the yoke 52 resting on top of the horn die F. Y

- With the parts in the position shown in Fig. 2, and the center of the pipe resting on the curved bending surface 0 of the sink 15 of the stationary die, the die (2 is moved toward the pipeso as to engage the outer end thereof. Continued movement of the die l2 wil1 uniformly bend both ends of the pipe intothe tangents-B ofthegsinks ,zgsregsme t5; As: this movement progresses, the". horn die if: will follow the bendbecause the pin 38; will ride; inwardly in the slots 39.: while the guide face 36' rides along the edges of; the plates 30.; The movement. is continued until the edges A. and: B of thedies: H and. i2 contact at which time the bend will. be: completed. As' the bend. progresses from the position shown in Fig. 2 to the. position shown inzFig. 3', the outer medial section of the pipe will be bent along the. curved face 46 and will constitute the entire curvature or: bend oii-thetpipebecause each end of the pipe; beyond the curvedface will: be bent at. a: tangent by reason of the tangents D of the sinks l5. lftiwili be noted that as the'bendingof. thepipe progresses, stock: will be drawn fromeach' end of pipe toward: the outer medial. portion which will; result in uniform wall thickness and when the; bend: is. complete, the edges of. the. ends will be. substantially at right'angles to the: tangents at the bend; Byr observing Fig. 2. it will be observed that the ends of the pipe section diverge and: when; th forming die I2 is moved inwardly the ends of the pipe will be simultaneously engaged which will cause said ends to follow the curvature. of. the sink l5, toward the center thereof, due to the fact that the center or inner bend of the pipe section rests against the fixed fulcrum of the die I I and also, due to the support givenby-the curved face d6 of the horn die E. By swinging: on rocking the horn die E gradually as-zthe: bending operation proceeds, a relatively smooth bend will be obtained. When the bend fias beerp brought to the position shown in Fig. 3, thecylind'er' ll of the horn die F is operated to extend the plunger 2B whereby said die is moved toward the plug ll. sufficiently topermit the yoke to then onto the shank. 55 immediately behind said die. Then by retracting the plunger zlllgthe" die F will pullthe plug 41' out of the pipe whereby itmay be removed to a'convenientplace. The. cylinder I] is again operated to cause the horn die F to enter the adjacent tangential end of the bent pipe, the plunger it having been previously operated to withdraw the horn die E sovv that the position shown in Fig. 4 is reached. The purpose in running the horn die B into the pipe bend, is to iron or round out any distortions occurring during the bend and to assure a relatively smooth finish. It is particularly stressed that the horn die F is not employed in bending the pipe and is used as a finishing tool. By employing a single die during the bending operation, a much smoother and mor uniform bend can be obtained as well as one of short radius.

Actual operation has demonstrated that the inner bend will be smooth and of uniform wall thickness and the whole operation may be quickly and easily performed. It has been found that pipe bends can be produced at any angle up to 90 without excessive thinning of the outer medial portion or excessive upsetting of the inner wall. After the horn die F has completed its work, it is returned to its normal position shown in Fig. 2, whereupon the forming die l2 may be moved away from the die H and the pipe bend taken out of the apparatus.

It is pointed out that by reason of the fixed fulcrum at the center of the sink l5 of the forming die I I, such fulcrum being short owing to the tangents D of said die, the inner bend of the pipe is made on a short radius. Since the face 46 of the horn die E is substantially equal in length to the entire length of the outer bend and this die swings from the position shown in Eig. 2. to the: position: shown in; Eli-gr; 3;. the: entire bending of the: pipe; is controlledsfromi one.- end thereofi. constrast tothose ma-clnnes which used horn dies at both endsiof-the-pipew The foregoing description of the invention is explanatory thereof and-various: changes in the size, shape and materials, aswellassinthe: details of; the. illustrated: construction may be made, within the scope'of the appendedclaims; without departing from the spirit of the: invention:

What I claim and desire to secure by Letters Patentilis-r' 1 apparatus for forming pipe. bends; including apa-ir' of. dies each having a sink'struck on the! contour of. the completed bend; a. horn diehaving a curvedface substantially equal in lengthto the entire outer curvature of. the: com:- plete: bend, means for moving the horn; dia in a. rightv line, means for angularl'y adjusting =the horn: die with: relation to its right line movement,. a: second: horn die having a curved face conforming to? the arc of the entire outer; bend of apipe; section, and means for forcing the sec- 0nd horn dieinto a pipetbend' toremove-distorstions; therefrom after the first horn diehas been removed.

2.. An apparatus for bending a section of. pipe on ashort radius? at its medial portion including, a. pain of forming. dies having sinksifor 1 .866530:- ing a" pipe. section, means for'moving one of the forming dies toward the other: forming die: to bend both ends: of. a pipe.- section at theiisa-m'e time on. a. short radius at its. medial portion, a movable horn: die having a curved face substantially equal in: length to the length of the; outer bendfon internally supporting: the outerbend. of a pipe sectionon each side'of the transverse axis of the, bend While the: pip section is-being bent by the: forming.- die, means. for removing. the horn dies after a pipe bendhasbeen completed, and a second horn-z die having a curved face comple men-tary to. the. face of the first. horn die andinsertable in a bent pipe section to remove distortionsttherefromi I apparatus for bending a right linesectiorr. of pipe including, a. stationar forming dieh'aving a. sink with a convex medial portion, a movable; die= having a sink with: a concavedme dial portion and movable toward the stationary die, a horn die having a curved face and movable in a right line, and means for supporting the horn die to swing laterally, whereby said horn die may be inserted in the right line pipe and swung when the movable die is moved toward the stationary die to bend the pipe section.

4. The method of forming pipe bends on a short radius which includes, heating a pipe to a bending temperature, constantly supporting the inner medial portion of the pipe on a fixed fulcrum having the curvature of the completed inner bend, internally supporting the outer medial portion andone end of a pipe on a constant surface curved to the arc of the completed outer bend of the pipe, internally supporting the opposite end of the pipe and simultaneously bending in a singl operation both ends of the pipe at tangents to the medial bend of said pipe by constantly applying pressure to the pipe in a right line direction.

5. The method of forming pipe bends as set forth in claim 4, with the step of maintaining the original internal diameters of the pipe ends while bending them,

6. The method of forming pipe bends as set 7| forth in claim 4, with the step of withdrawing theiconstant outer bending surface from the completed pipe bend while supporting the pipe throughout its length, then withdrawing the support from theoppcsite end of the pipeand then subjecting the inner surface of the outer pipe bend to a surface curved to the arc of the outer bend to round the pipe. I 7. The method of forming pipe bends on a short radius which includes, heating a pipe to abending temperature, constantly supporting the inner medial portion of the pipe on a fixed fulcrum having the curvature of the completed inner bend, internally supporting the outer medial portion and one end of a pipe on a fixed surface curved to the arc of the completed outer bend of the pipe, internally supporting the opposite end of the pipe, and gradually and simultaneously bending both ends of the pipe while gradually swinging the constant surface of the outer bend support in an arc transverse of the longitudinal axis of the pipe being bent to compensate the bending of the ends of the pipe. 8. An apparatus for forming pip bends including, a pair of forming dies each having a sink struck on the contour of the bend to be completed, one of which dies is stationary and the other of which dies is movable, a horn die having a curved face substantially equal in length to the entire outer curvature of the complete bend, and means for moving the horn die between the sinks of the forming dies, said horn die being mounted to swing on said moving means inan arc transverse of the longitudinal axis of the bend when the forming dies are being closed.

9. An apparatus as set forth in claim 8, and a removable plug for insertion in the end of the pipe to be bent opposite the horn die. 10. An apparatus for bending a section of pipe on a short radius at its medial portion including, a pair of forming dies having sinks for receiving a pipe section, means for moving one of the forming dies toward the other forming die to bend both ends of a pipe section at the same time on a short radius at its medial portion, a

horn die adapted to be inserted in one end of 43 Number a' pipe section to be bent and having a curved face for internally supporting the outer bend of a pipe section on each side of the transverse axis 0f the bend,- a support having an arcuate guide transverse to the movement of one of the form ing dies, and a member carried by the horn die movable along said support guide while the'pipe section is being bent by the forming dies; 11. An apparatus as set forth in claim 10, and a removable plug for insertion in the end of the pipe to be bent opposite the horn die.

12. A horn die device for a pipe bending apparatus including, a movable support, a carrier mounted on the support having an arcuate guide, and a horn die having an arcuate face at one end and its opposite end being movable in the carrier and along said arcuate guide. r v

13. A removable plug device for a pipe bending apparatus including, a plug adapted tube inserted in the end of a pipe, a yoke spaced'from the plug adapted to be removably mounted-on one of the dies of a pipe bending apparatus, and an elongate connection pivoted at one end to the outer end of the plug and hinged at its opposite and to the yoke. l CLINT CROSS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 174,609 Wright Mar. 7, 1876 785,082 Brinkman Mar. 21, 1905 856,847 Connors June 11, 1907 951,717 Andres Mar. 8, 1910 953,253 Brinkman Mar. 29, 1910 1,370,075 Vasselli Mar. 1, 1921 1,680,008 Bohlin-g Aug. 7, 1928 1,781,567 Bohling Nov. 11,1930 1,816,218 Henry et a1 July 28, 1931 1,908,373 Loepsinger May 9,1933 1,923,272 Maroto Aug. 22, 1933 1,993,361 Cornell, Jr. Mar, 5, 1935 FOREIGN PATENTS Country Date 17,723 Great Britain 1. 1891v 276,537 Germany July 14, 1914 

